Geek talk (Science/Space/Tech etc)

The first image of the event horizon will be published tomorrow


Post about it when it happens

okay boss

Here’s some prep for you lot

Genuinely please do, I’m looking forward to seeing this, but cba finding a stream or whatever and will be busy when it’s on :arteta:


well to keep your expectations in proportion: first of all we’re not taking a picture in the classic sense since Sag A* does not reflect light (obv.), secondly it is not taken in visual but in radio either way. It is taken by an array (a network of them world wide) led by ALMA (in Chile). The reason we do radio instead of optical is because the object is in the disc and we’re in the disc and the disc is full of dust (it’s about 25000 light years of dust between us), dust scatters away optical light so we would never see anything in optical, but radio doesn’t care about dust. Because radio waves are huge (while optical are in the nanometer range, the actual radio waves can be as huge as hundreds of km, but in this specific case it is in few mm band I think which is closer to IR), it is a) sometimes to big to collect with a regular round mirror the type you usually think of with a telescope, but either/or we can b) use large arrays of them over huge fields, or, as in this case, use several arrays and grids all over the planet, and combine it to the same picture, and c) they’re in the band that passes through the atmosphere so we can do it from Earth rather than having to do it in space.

However, since we can’t see this thing in any band either way, what we will do is to concentrate the huge array network to map the surrounding area outside the edges most likely, probably some catch the edges of the accretion disc around it, use it tog. with gravitational mapping etc. to ‘draw a picture of the extent of the object’ and then the magic happens:

you’ll get some sweet pics which are an artist’s rendition (hopefully not) or you’ll get some colour manipulated images based on gravitational field mapping etc. to make it look sexy or w/e (this is what I expect). For me, best thing would be some more honest picture from pixel mapping with colour coding on so that it looks like a super nintendo game picture but it is what we actually see.


Yeah whatever information we have about outer space are basically just numbers beyond a certain point.

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we can see things in many/all bands, the ones we do not see from Earth we see from space (like with the HST or JWST soon), it’s just that if the objects are in our own galaxy (as in, within the disc), dust is a problem for a range of bands, like visual, so we can’t do those bands. If you look at other things you can look at them just fine and get decent pictures depending on distances and so forth.

The reason here to get an “image” with things like mapping the gravity field is that in order to map the gravity field we need to take several pictures over time, to study how things near the BH orbit etc. and use that info to map the object. You couldn’t do that with just one image, but you could add info from older studies and combine with a newer image set etc.

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Nah I’m messing about. That is legitimately interesting

Yeah, explained well here

You saying that has given me the urge to re-read a Bill Bryson book I read years ago. Although I find his writing style quite arrogant he always made me want to buy a telescope and try spotting supernovae

Maybe when I’m old and retired

yes I like her explanation, that’s how it works.

Thread made. Had no idea what to name the thread, hope it will do :sweat_smile:

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Cool thread. Anyone watch Issac Arthur’s excellent YouTube channel?

I like it :sweat_smile:

Here’s a fun fact to get a few people intrigued:

The commonly known tongue twister ‘she sells seashells on the seashore’ originates from a young girl in Dorset (named Mary a
Anning) who used would collect dinosaur fossils off the English coast and sold them to tourists.

Sorry to move into Geology…

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Yes! I read about this in A Brief History of Nearly Everything by Bill Bryson. Brilliant book.

It takes on a more sinister turn when it goes into the realms of Gideon Mantell and his hard work being undone by the vicious Richard Owen

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Yes, that’s the book I was referring to in my earlier post. Very dated (still very relevant though), and his writing style is an acquired taste but very insightful! Been years since I read it but it’s given me the bug to re-read it

The image, captured by the Event Horizon Telescope, will show the black hole at the center of the Milky Way, and will be shown in a press conference beginning at 9am ET (2pm BST) on April 10. When the conference begins, you will be able to watch the live stream below.

Think only about an hour away from a historical moment

wow. historical moment. well, love the positivity :sweat_smile: